OpenGL Love from Valve and Crytek
Valve invests a lot into Linux gaming these days, as it wants to reduce Microsoft's grip on PC gaming. The dedication to Linux also means the need to use OpenGL instead of Windows exclusive DirectX. Valve ported their games to OpenGL and have developed a limited porting code for the job. Called "ToGL", it handles transition from Direct3D calls to OpenGL ones.
Now, to support the efforts of other developers most of this code is available on GitHub. The released code is slightly incomplete and is very closely tied to the needs of Source engine. While it will not allow other devs to port their games to Linux in a day, the code should help them a lot with the process. With this release, it is reasonable to expect more interest in future porting to Linux.
While Valve's efforts are likely to help mostly older games, Crytek's new announcement is more relevant for the future. During GDC next week, the full native Linux support in CryEngine is going to be demonstrated. Considering, how they focus on making cross-platform development as easy as possible, many devs may create Linux versions of their games with minimal additional work. Overall, these announcements mean that Linux and thus SteamOS's game library is getting considerably larger in the near future.